Is there a weight limit for the rifle?
I've seen a few 4, 5, and 7 inch wide Light Gun forearms, but most are on Heavy Guns. Bald Eagle use to make a wide windage top; it would take up to a 7-inch wide forearms. Narrower forearms used the same top & just had more material in the side portion of the bag.
The 4-inch can be taken care of with a custom bag to fit a regular 3-inch top... Like Tooley/Fletcher's "Torque Tamer" stock.
FWIW